Method and device for distributing a lumpy bulk material

ABSTRACT

The invention relates to an apparatus and a process for distributing a lumpy bulk material, in particular iron ore which has been at least partially prereduced, onto an extensive surface, in particular onto a fixed bed, this surface extending within a reactor or vessel used in physical or chemical process technology, in particular in a reactor used in a metallurgical plant to produce pig iron or primary steel products, and the lumpy bulk material being charged via at least one charging apparatus, which has at least two, in particular rotationally symmetrical, chutes, which are preferably arranged at the same distance from the vertical longitudinal axis of the reactor. In this arrangement, at least a proportion of the bulk material, in particular after it has been introduced into the chute, before it comes into contact with the extensive surface, is distributed in the radial and/or tangential direction—as seen from above—at a scattering device which is assigned to at least one of the chutes and is preferably in the chute.

The invention relates to an apparatus and a process for distributing alumpy bulk material, in particular iron ore which has been at leastpartially prereduced, onto an extensive surface, in particular onto afixed bed, this surface extending within a reactor or vessel used inphysical or chemical process technology, in particular in a reactor usedin a metallurgical plant to produce pig iron or primary steel products,and the lumpy bulk material being charged via at least one chargingapparatus, which has at least two, in particular rotationallysymmetrical, chutes, which are preferably arranged at the same distancefrom the vertical longitudinal axis of the reactor.

The invention also relates to new types of scattering devices.

The distribution of a lumpy bulk material on an extensive surfacerepresents a problem which is known in plant construction and in processengineering. Particularly in the case of reactors used inchemical/physical process engineering, considerable efforts are beingmade to achieve a degree of distribution of the bulk material which isoptimized for the particular process. Incorrect loading of a reactor ofthis type may lead to a reduction in the quality of the product producedand also to a significantly higher level of environmental pollution, forexample caused by higher dust emissions. The productivity of aninstallation of this type is adversely affected as a result.

U.S. Pat. No. 4,497,609 describes an apparatus by means of which astream of bulk material can be charged continuously into a shaftfurnace. For this purpose, bulk material is charged on the periphery ofthe shaft furnace via a plurality of chutes.

In view of the prior art, it is an object of the present invention tofurther develop a process according to the preamble of claim 1 and anapparatus according to the preamble of claim 4 which, compared to theprior art, lead to improved process management and a more economicconfiguration of the installation.

The object which has been set is achieved, according to the invention,using the process according to the characterizing part of claim 1 andusing the apparatus according to the characterizing part of claim 4.

It is a further object of the invention to develop scattering devices inaccordance with the preamble of claim 12 or 13 which are simple to use.This object is achieved by corresponding scattering devices according toclaim 12 or 13.

The present invention has proven particularly advantageous when used ina melter gasifier, and is documented in most detail in this respect.However, the use of the invention is not restricted to this embodiment,but rather the description of the operations which take place in amelter gasifier represents an explanation given by way of example. Theuses of the invention in other metallurgical units, in particular ashaft furnace, form further concrete embodiments of the invention.

A melter gasifier is a unit for producing pig iron or primary steelproducts, as has long been known in the prior art.

The melter gasifier, as described in the prior art, is used to melt downa substantially prereduced iron ore (DRI), and to generate reduction gasfrom reduction-gas carriers, preferably lumpy coal.

The coal and the DRI are generally introduced into the melter gasifiervia the dome of the latter, and it has proven expedient for the coal tobe introduced centrally.

Accordingly, the DRI is introduced into the melter gasifier via one ormore eccentrically located openings on the gasifier dome.

According to one embodiment of the process according to the inventionfor distributing a lumpy bulk material, in particular iron ore which hasbeen at least partially prereduced, is distributed onto an extensivesurface, in particular onto a fixed bed, this surface extending within areactor or vessel used in physical or chemical process technology, inparticular in a reactor used in a metallurgical plant to produce pigiron or primary steel products, and the lumpy bulk material beingcharged via at least one charging apparatus, which has at least two, inparticular rotationally symmetrical, chutes, which are preferablyarranged at the same distance from the vertical longitudinal axis of thereactor, in which process, furthermore, at least a proportion of thebulk material is distributed in the radial and/or tangentialdirection—as seen from above—at a scattering device.

According to a further feature of the process according to theinvention, the bulk material is distributed at the scattering device atleast partially inside the chute.

According to a further feature of the process according to theinvention, the scattering areas of adjacent chutes overlap at leastpartially before the fixed bed is reached.

According to an additional feature of the process according to theinvention, the overall scattering pattern of all the chutes as seen fromabove substantially forms a concentric ring.

The invention is also characterized by an apparatus according to theinvention for distributing a lumpy bulk material, in particular ironsponge, from a flow of bulk material onto an extensive surface, inparticular onto a fixed bed, this surface extending within a reactorused in physical or chemical process engineering, in particular within areactor of a metallurgical plant for producing pig iron or primary steelproducts, preferably in a melter gasifier, and the lumpy bulk materialbeing charged via a charging apparatus which has at least two,preferably rotationally symmetrical, chutes, and the charging apparatusfurthermore has at least one additional scattering device for scatteringthe bulk material, by means of which at least a proportion of the bulkmaterial can be distributed in the radial and/or tangential direction,as seen from above.

The distribution of a bulk material via a plurality of chutes orinclined tubes has long been known in process engineering, in particularin metallurgical technology.

The additional provision of a scattering device causes the bulkmaterial, as it drops out of the chutes onto the surface, to beadditionally scattered, or the streams of bulk material formed in thisway to be widened.

According to a particularly preferred embodiment of the invention, thewidened streams of bulk material overlap one another. This ensures inparticular that, even in the event of a chute failing, for example as aresult of becoming blocked, the fixed bed receives a substantiallyuniform feed of bulk material.

To achieve scattering which is as uniform as possible, distribution inthe radial and tangential directions—as seen from above—is particularlysuitable, although both radial distribution and tangential distributionused individually also lead to the flow of bulk material being widenedand to the bulk material being scattered, although to a limited extent.

According to one feature of the invention, the chutes are arranged atthe same distance from the longitudinal axis of the reactor.

Particularly preferably, the bulk material is in this case dischargedonto the fixed bed at a plurality of points along an imaginary circle orring, in which case, according to a further preferred embodiment, theindividual flows of bulk material assigned to the chutes partiallyintersect one another. In this way, it is possible to compensate for thefailure of one or more chutes during the charging of the fixed bed.

According to one feature of the invention, the scattering device isarranged in a rigid manner.

Particularly at relatively high temperatures, moveable devices, forexample in relevant reactors used in metallurgical technology, haveproven to be relatively unreliable. It is necessary to take particularprotective measures (with regard to temperature, wear), which entailconsiderable costs.

By contrast, an immobile, i.e. rigid, apparatus is inexpensive andreliable.

According to a further feature of the invention, the scattering deviceis arranged so as to be moveable, but without a mechanical drive, inparticular without any drive. In this case, according to a preferredembodiment of the invention, the scattering device is rigidly secured.

According to one feature of the invention, the scattering device isarranged inside the chute. This ensures that the scattering device isnot exposed to the high temperature of the melter gasifier. Inparticular, in this case the high radiant heat as occurs in a meltergasifier, causing a high load on all the internal fittings, in the gaschamber is to be taken into account. Installing the scattering device inthe chute means that the scattering device is effectively protected fromthese thermal or thermo-mechanical loads and achieves a long servicelife.

According to a further feature of the invention, the scattering devicehas a number of projections which are arranged on the inner side of thechute.

The projections cause the material in the chute to be decelerated and,in particular, be charged onto the fixed bed along a circular ring at apredetermined distance from the centre of the gasifier. According to apreferred embodiment, the wear-resistant projections are fitted in thelower part of the chute.

According to a further feature of the invention, the scattering devicehas a chain, preferably a round-link chain.

The chain represents a simple and inexpensive alternative allowing thematerial in the chute or inclined tube to be decelerated, and in thisway allowing the desired charging along the circular ring to beproduced. The chain is in this case made from heat-resistant andwear-resistant material.

According to a further additional feature, the chain, at predeterminedintervals, which preferably vary with respect to one another, has anumber of scattering elements, for example nodules.

This ensures that particularly uniform scattering is achieved.

The invention is also directed to a scattering device.

According to a particular embodiment, the scattering device has a numberof chains, on each of which, in turn, a number of nodules are provided,and adjacent nodules are arranged at intervals which preferably differfrom one another.

The scattering device according to the invention causes the bulkmaterial to be decelerated and scattered, and in this way causes theresulting flow of bulk material which strikes the fixed bed to bewidened.

A particular embodiment provides a device which is used to guide andscatter the bulk material, this device having a chute, and a number ofprojections being arranged on the inner side of the chute.

Non-restrictive exemplary embodiments of the invention will be explainedin more detail below with reference to diagrammatic drawings, in which:

FIG. 1 diagrammatically depicts the feeds and a discharge line and tapin a melter gasifier,

FIG. 1A is a plan view of the melter gasifier,

FIG. 1B is a plan view of an exemplary DRI distribution on a fixed bedof the melter gasifier,

FIG. 2 shows an exemplary embodiment of a device for combined guidanceand scattering,

FIG. 3 shows an exemplary embodiment of a scattering device,

FIG. 3A is an enlarged view of a portion of FIG. 3 showing chains andnodules on the chains included in the scattering device.

The melter gasifier has feeds for coal 1, for DRI 6, for dust 2, foroxygen 3, as well as a slag and pig iron tap 4 and a gas discharge line5 for discharging the reduction gas. Both the coal and the DRI areintroduced continuously into the melter gasifier. Each feed 6 for theDRI has an opening 6 a in the gasifier dome, there being six openings ata distance 16 from the coal-introduction means which is oriented alongthe longitudinal axis, and which are equipped with chutes or inclineddownpipes 6 b. Only partial sections of the chutes or inclined downpipes6 b are shown in FIG. 1A in order to clearly show openings 6 a. For thesake of clarity, in FIG. 1 two feeds 6 for DRI are illustrated and areintended to represent all the feeds 6 for DRI.

The DRI is passed through 6 chutes, which are each secured to thegasifier dome in the corresponding opening, each chute having, on itsinner surface, projections which are used to scatter the DRI.

The DRI is distributed along an imaginary circle or ring onto the bed ofthe melter gasifier, without any DRI being charged into the centre. Thedistribution of the DRI is diagrammatically illustrated in FIG. 1B, inwhich the DRI distribution 7 on the fixed bed is diagrammaticallysketched. Accordingly, the scattering of the DRI in the chutes, comparedto the prior art, results in an increase in the scattering radius of theDRI on the fixed bed, with the individual scattering areas partiallyoverlapping one another. The scattering according to the invention leadsto uniform distribution and, in particular, improved mixing of the DRIwith the coal which is introduced.

FIG. 2 diagrammatically depicts a device according to the invention forguiding and scattering the DRI. This device is a chute 8, on the innersurface of which a plurality of projections 9 are arranged. If the DRIis passed through this chute, it is diverted and decelerated by theprojections.

All parts of the apparatus presented here have to be adapted to theprevailing conditions in their particular area of use. When used in amelter gasifier, materials which withstand high temperatures and arewear-resistant are predominantly used. Furthermore, consideration may begiven to providing those parts which are exposed to particularly hightemperatures with a refractory lining.

Those parts of the apparatus illustrated here which experience has shownare exposed to particularly high levels of wear are additionallyprotected by reinforcements, for example by welded-on plates.

FIG. 3 shows an embodiment of a scattering device as is used, forexample, in a melter gasifier for introducing the DRI onto the fixedbed. In this case, one or more chains 13 are arranged in a chute 10 bysuitable securing means 11 in a protective pipe 12.

According to a preferred embodiment, the chains have a plurality ofnodules 15 as shown in FIG. 3A. In this case, the distances between thenodules preferably vary. The bulk material which is introduced into thechute 10 via a feed line 14 is decelerated and scattered by the chainsand/or the nodules of the chains.

1. A process for distributing a lumpy bulk material onto an extensivesurface, wherein the surface extends within a reactor or vessel used inphysical or chemical processing, and the vessel having a verticallongitudinal axis; the process comprising: charging the lumpy materialinto the vessel via respective chutes at at least two locations of thevessel and the locations being spaced at a distance from the verticallongitudinal axis of the reactor and above the surface, and after thematerial has been introduced into the chutes and before the materialcontacts the extensive surface in the vessel, scattering at least aportion of the lumpy bulk material entering via at least one of thechutes for increased scattered distribution of the lumpy material overthe surface, the scattering being in at least one of the radial andtangential directions with respect to the surface in the vessel forincreasing the cross-sectional area of flow of the lumpy materialtraveling through each one of the at least one of the chutes, whereinthe cross-sectional area of flow is measured perpendicularly to thedirection of flow of the lumpy material, and selecting the locations ofcharging of the bulk material into the vessel so that the scatteringprocess is of sufficient extent that scatter areas on the surface formedby adjacent locations of charging of lumpy material cause partialoverlap of the scatter areas of adjacent areas of charging even beforethe lumpy material reaches the surface in the vessel.
 2. The process ofclaim 1, wherein the charging locations are rotationally symmetricallocations around the longitudinal axis of the vessel.
 3. The process ofclaim 2, wherein the charging locations into the vessel are all at thesame distance from the vertical longitudinal axis of the vessel.
 4. Theprocess of claim 3, wherein the charging locations of the lumpy materialin the vessel and the scattering process are respectively so designedand selected that an overall scatter pattern of lumpy material generatedthrough all of the charging locations produces substantially aconcentric ring on the surface.
 5. The process of claim 2, furthercomprising introducing coal into the vessel along the centrallongitudinal axis.
 6. The process of claim 1, wherein the scattering isdone at the chute.
 7. The process of claim 1, wherein the lumpy bulkmaterial used in the process comprises iron ore which has been at leastpartially prereduced and wherein the reactor or vessel is a reactor usedin a metallurgical plant to produce pig iron or primary steel products.8. Apparatus for distributing a flow of lumpy bulk material onto anextensive surface in a reactor vessel, wherein the vessel has thesurface therein on which the material is to be distributed, theapparatus comprising: a charging apparatus for the vessel comprising aplurality of chutes fixed in place relative to the vessel for charginglumpy bulk material into the vessel, the chutes being at locationsrelative to the vessel such that the lumpy material is distributed overthe surface; a scattering device operatively associated with one of thechutes for scattering the bulk material entering the vessel through thechute for increasing the distribution of at least a portion of the lumpymaterial in at least one of the radial and tangential directions of thesurface in the vessel, the scattering device being operable to increasethe cross-sectional area of flow of the lumpy material traveling throughthe chute, wherein the cross-sectional area of flow is measuredperpendicularly to the direction of flow of the lumpy material, andwherein the scattering device is moveable in the chute.
 9. The apparatusof claim 8, wherein the vessel has a vertical longitudinal axis and thechutes are arranged in a rotationally symmetrical manner around thelongitudinal axis of the vessel.
 10. The apparatus of claim 9, whereinthe chutes are at the same distance from the vertical longitudinal axisof the vessel.
 11. The apparatus of claim 8, wherein the scatteringdevice for one of the chutes is arranged in the chute.
 12. The apparatusof claim 8, wherein the scattering device comprises a chain in thechute.
 13. The apparatus of claim 12, further including a plurality ofscattering elements at intervals along the chain.
 14. The apparatus ofclaim 13, wherein the scattering elements comprise nodules on the chain.15. The apparatus of claim 13, wherein the scattering elements arespaced at varying intervals along the chain.